166 Dr. Bashford, Mr. Murray, and Dr. Cramer. [Dec. 10, 



successful inoculation of Jensen's tumour fluctuated between 20 and 90 per 

 cent, of the number of animals inoculated. 



In a series of papers* we have drawn attention to the greater susceptibility 

 of young than old mice, to the important influence on the success of trans- 

 plantation, of the character and phase of the tumours inoculated, the dosage, 

 and site of inoculation. In the course of a careful study of the process of 

 absorption of tumours after exposure to radium, we showed its identity 

 with localised changes in the majority of propagated tumours, changes 

 which were found to have become general in the only case we had then 

 noted where a tumour of three weeks' growth and of 1 cm. diameter had 

 actually diminished in size.f While recognising the importance of 

 haemorrhage as an integral part of the process of absorption both when 

 spontaneous and following exposure to radium, we pointed out that the phase 

 of growth of the tumour was also of great and probably decisive importance. 

 These observations harmonised well with Jensen's experience, and tended 

 to explain the irregularities in the disappearance of tumours under his 

 observation. Our position was summarised as follows : — " No conclusion has 

 yet been arrived at as to what are the essential and what the subsidiary 

 features in this prolonged proliferation. The variations make it difficult to 

 correlate different observations, and to be sure of their proper interpretation. 

 Efforts to influence growth by immune (cytolytic) serum and other means 

 have, in consequence, not yet led to any definite conclusion." 



ClowesJ working also with Jensen's tumour, obtained 30 per cent, of 

 success in normal animals. He recorded spontaneous absorption in from 

 15 — 20 per cent, of his transplanted tumours. The animals in which 

 spontaneous absorption had occurred were stated to possess a specific anti- 

 body in their serum, which, on injection into animals with transplanted 

 tumours, exerted a curative effect. In only one case out of 20 mice so 

 treated had the beneficial influence of the immune serum been missed. In 

 view of the low percentage of success obtained, the slow development of the 



* First and Second Scientific Reports of Imperial Cancer Research Fund, 1904, 1905 ; 

 ' Roy. Soc. Proc.,' B, vol. 78, 1906. 



t We recorded the precautions we had taken in searching for tumours undergoing 

 spontaneous absorption. Clowes has taken this criticism of our own procedure as imply- 

 ing that in our opinion his "spontaneous recoveries were ulcerations" ('Brit. Med. 

 Journ.,' December 1, 1906). Regression of inflammatory swellings may take place without 

 ulceration, and our remarks apply to our own doubtful "tumours" of less than 14 days' 

 growth, within which time Clowes made no mention of tumours having appeared. 



| " Preliminary Communication regarding an Immune Body Capable of Inhibiting the 

 Development of Cancer in Mice," ' Johns Hopkins Hosp. Bull.,' April, 1905 ; " Further 

 Evidence of Immunity against Cancer in Mice after Spontaneous Recovery," Clowes and 

 Baeslack, ' Medical News,' November 18, 1905. 



